A method of performing a resolution enhancement technique such as OPC on an initial layout description involves fragmenting a polygon that represents a feature to be created into a number of edge fragments. One or more of the edge fragments is assigned an initial simulation site at which the image intensity is calculated. Upon calculation of the image intensity, the position and/or number of initial simulation sites is varied. New calculations are made of the image intensity with the revised placement or number of simulation sites in order to calculate an OPC correction for the edge fragment. In other embodiments, fragmentation of a polygon is adjusted based on the image intensities calculated at the simulation sites. In one embodiment, the image intensity gradient vector calculated at the initial simulation sites is used to adjust the simulation sites and/or fragmentation of the polygon.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method of preparing a layout data file defining features to be created via a photolithographic process for optical and process correction, comprising: reading at least a portion of a layout file defining one or more features to be created; fragmenting the features into a number of edge fragments; defining initial simulation sites for one or more of the edge fragments; estimating an image intensity at the initial simulation sites; adding additional sample points to one or more of the simulation sites dependent on the estimated image intensity; recalculating image intensities at at least one of the additional sample points; determining how to move one or more edges for a resolution enhancement technique based on the recalculated image intensities; and fabricating a mask or reticle using a stored layout data file comprising at least one of the moved edges or providing the stored layout data file comprising at least one of the moved edges to a manufacturing facility for fabricating photolithographic masks or reticles.
A method to improve photolithography mask creation refines the design layout through simulation. It involves reading the layout, then fragmenting the shapes into smaller edge pieces. Simulation sites are assigned to these edge fragments, and the light intensity is estimated at these sites. To increase simulation accuracy, additional sample points are added around the simulation sites based on the initial light intensity estimates. Light intensity is recalculated at these new points. Finally, the edges are adjusted to optimize the final mask, and the mask is fabricated or the modified layout file is sent to manufacturing.
2. The method of claim 1 , wherein the estimate of the image intensity is made by computing an image intensity gradient vector at the simulation sites.
The method of preparing a layout data file where image intensity is estimated by calculating an image intensity gradient vector at the simulation sites. This means the change in image intensity is calculated as a vector, providing both magnitude and direction of the intensity variation around the simulation site, allowing for more informed placement of additional sample points for improved accuracy in optical proximity correction.
3. The method of claim 2 , wherein the additional sample points are added if the image intensity gradient vector has an angle that exceeds a threshold.
The method of preparing a layout data file including calculating the image intensity gradient vector, adds additional sample points only if the angle of the image intensity gradient vector exceeds a set threshold. This means if the direction of the intensity change is sharp enough (beyond the threshold), more samples are added, focusing computational resources on areas with potentially significant optical effects.
4. The method of claim 2 , wherein the additional sample points are added if the image intensity gradient vector has a magnitude that exceeds a threshold.
The method of preparing a layout data file including calculating the image intensity gradient vector, adds additional sample points only if the magnitude (strength) of the image intensity gradient vector exceeds a defined threshold. This focuses the addition of sample points on regions where the image intensity is changing rapidly, improving the accuracy of the simulation in these critical areas.
5. The method of claim 1 , wherein the additional sample points are added if the estimated image intensity varies by more than a predetermined amount.
The method of preparing a layout data file adds additional sample points if the estimated image intensity varies significantly (more than a predetermined amount). This adaptively increases the simulation resolution in regions where the optical behavior is complex or unpredictable, enhancing the accuracy of the optical proximity correction.
6. The method of claim 1 , wherein the additional sample points are added if the estimated image intensity varies by more than a predetermined amount along the length of the simulation site.
The method of preparing a layout data file adds additional sample points if the estimated image intensity changes significantly along the length of the simulation site (more than a predetermined amount). This specifically targets regions where the image intensity profile is not uniform across the simulation site, enabling a more accurate representation of the optical effects along the edge.
7. The method of claim 1 , wherein the additional sample points are oriented in a direction perpendicular to the length of the edge fragment.
The method of preparing a layout data file adds additional sample points that are placed in a direction perpendicular (90 degrees) to the length of the edge fragment. By placing the samples perpendicular to the edge, the simulation captures intensity variations that directly affect the edge placement and shape fidelity.
8. The method of claim 1 , wherein the additional sample points are oriented in a direction parallel to an edge fragment of the fragmented feature.
The method of preparing a layout data file adds additional sample points that are placed in a direction parallel to the edge fragment. Sampling along the edge helps capture variations in image intensity that may impact line-end shortening or other edge-related effects during manufacturing.
9. The method of claim 1 , wherein the additional sample points are added adjacent to original sample points of the initial simulation sites.
The method of preparing a layout data file adds additional sample points that are placed directly next to the original simulation points. This local refinement strategy concentrates computational effort around the existing simulation sites, leveraging the initial intensity estimates to efficiently improve accuracy.
10. The method of claim 1 , wherein the additional sample points are positioned on either side of an initial simulation site.
The method of preparing a layout data file adds additional sample points that are positioned on both sides of the initial simulation site. This balanced approach allows for capturing image intensity variations symmetrically around the original point, reducing bias in the simulation results.
11. Computer readable storage or memory storing data defining a layout for a number of features to be created via a photolithographic process, wherein said data is created by: reading at least a portion of a layout file defining one or more features to be created; fragmenting the features into a number of edge fragments; defining initial simulation sites for one or more of the edge fragments; estimating an image intensity at the initial simulation sites; adding additional sample points to one or more of the simulation sites dependent on the estimated image intensity; recalculating image intensities at at least one of the additional sample points; determining how to move one or more edges for a resolution enhancement technique based on the recalculated image intensities; and storing the layout data file in computer-readable memory or storage, the stored layout data file comprising at least one of the moved edges and being suitable for manufacturing a mask or reticle with a mask writer tool.
A computer storage medium (memory, disk) stores layout data for photolithography, created by a process: reads the layout, fragments shapes into edges, assigns simulation sites, estimates light intensity. Then, adds more sample points to simulation sites based on intensity estimates, recalculates intensities at these new points, adjusts edges based on these recalculated intensities for resolution enhancement, and stores the final layout. The layout contains adjusted edges suitable for manufacturing masks.
12. The computer readable medium of claim 11 , wherein said data is further created by computing an image intensity gradient vector at the simulation sites.
The computer readable medium storing data defining a layout for a number of features includes the computation of an image intensity gradient vector at the simulation sites. This gradient vector helps to understand both the magnitude and direction of image intensity changes, allowing for optimized placement of further sample points to improve simulation accuracy of the features on the mask.
13. The computer readable medium of claim 11 , wherein the additional sample points are added if the image intensity gradient vector has an angle that exceeds a threshold.
The computer readable medium storing data defining a layout for a number of features includes adding additional sample points only when the angle of the intensity gradient vector exceeds a certain threshold. This intelligently focuses simulation efforts on areas where there are rapid directional changes in light intensity, which are more likely to require correction.
14. The computer readable medium of claim 11 , wherein the additional sample points are added if the estimate image intensity varies by more than a predetermined amount along the length of the simulation site.
The computer readable medium storing data defining a layout for a number of features adds additional sample points if the image intensity varies by more than a predetermined amount along the length of the simulation site. This allows the software to focus on correcting areas where the light intensity is non-uniform, and therefore likely to result in defects or inaccuracies in the final mask.
15. The computer readable medium of claim 11 , wherein the additional sample points are oriented in a direction perpendicular to the length of the edge fragment.
The computer readable medium storing data defining a layout for a number of features adds additional sample points oriented perpendicular to the length of the edge fragment. This arrangement helps capture variations in the image intensity that are most likely to impact the accuracy of the edge placement on the final mask.
16. The computer readable medium of claim 11 , wherein the additional sample points are oriented in a direction parallel to an edge fragment of the fragmented feature.
The computer readable medium storing data defining a layout for a number of features adds additional sample points oriented parallel to an edge fragment. This helps capture any variations in image intensity running along the edge, which could lead to defects such as line-end shortening or corner rounding.
17. A method of preparing a file for a mask writing tool defining features to be created via a photolithographic process, comprising: transmitting at least a portion of the layout data file to a remote computer system for processing by: reading at least a portion of a layout file defining one or more features to be created; fragmenting the features into a number of edge fragments; defining initial simulation sites for one or more of the edge fragments; estimating an image intensity at the initial simulation sites; adding additional sample points to one or more of the simulation sites dependent on the estimated image intensity; recalculating image intensities at at least one of the additional sample points; and determining how to move one or more edges for a resolution enhancement technique based on the recalculated image intensities; and storing the data in the storage or memory, the data representing at least one of the moved edges and being suitable for use in manufacturing photolithographic masks or reticles.
A method for preparing a mask-writing file for photolithography involves sending layout data to a remote computer. This remote system: reads the layout, fragments shapes into edges, assigns simulation sites, estimates light intensity, adds extra sample points depending on estimated light intensity, recalculates intensity at the new points, and determines how to adjust edges for resolution enhancement. The resulting data, including moved edges, is then stored for making photolithography masks.
18. The method of claim 17 , further comprising receiving a modified layout data file generated based on using the additional sample points to simulate the features to be created via the photolithographic process.
The method of preparing a file for a mask writing tool further includes receiving a modified layout data file. This file is generated by using the extra sample points to simulate how the features will look when created via photolithography. The use of extra sample points in simulation improves the accuracy of the final mask design.
19. The method of claim 17 , further comprising manufacturing an integrated circuit comprising features created via the photolithographic process, based on a simulation using the additional sample points.
The method of preparing a file for a mask writing tool involves manufacturing an integrated circuit. The circuit features are created using photolithography, based on a simulation that utilizes the additional sample points. This ensures that the manufacturing process is optimized using enhanced simulation data, leading to a more accurate and reliable integrated circuit.
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June 6, 2016
July 11, 2017
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